Description
A precision six-millimeter barrel on a platform built for swapping. 416R stainless in the SOLGW Precision SPR contour, with SOLGW’s proprietary P3 polygonal three-groove rifling and a 1:7.5 twist — fast enough to stabilize the heavy end of the 6mm menu, which is the reason to be running six millimeters in the first place. 6mm Max® keeps the unmodified mil-spec .378 (5.56) bolt face, so changing barrels in your MRP™ upper does not mean changing bolt class.
SOLGW ladders gas length to barrel length across the Precision SPR range, and the 16″ takes the intermediate system on a 13.65″ tube — longer dwell and lower port pressure than a mid-length would give here, without asking a rifle-length system to work on a barrel too short to carry it. The shorter of the two lengths, and the easier one to carry.
The low-profile gas block is installed and pinned before shipment — port alignment verified, set screws torqued to specification, and a stainless steel coiled pin through block and barrel. Set screws clamp the block onto the journal; the pin stops rotation independent of clamping force.
Converted to the LMT® MRP™ barrel interface, then inspected, gauged and assembled by the Second of Ten build team to a documented standard. Installs with the MRP™ upper’s factory barrel hardware — no proprietary tooling and no permanent modification to the receiver. Headspace is gauged and recorded on the barrel inspection record before shipment.
Ships shooter ready: gas tube installed and the muzzle protected by the SOT Standard Barrel Thread Protector (CNC-machined steel, black or nitride finish), with no muzzle device fitted. Brakes, flash hiders and suppressor mounts are fitted and timed to order through the SOT Custom Shop. The protected bare thread is also the right configuration for a direct-thread suppressor. A headspaced bolt carrier group can be added and gauged to this barrel: SOT Enhanced Microbest C158 MPI DLC+, SOT Enhanced HM Defense in Black Nitride, or the SOT Enhanced Microbest Super-Stake with the Young Manufacturing HMB™ bolt.
At 16 inches this barrel builds a conventional rifle — no tax stamp, no registration and no wait. Requires 6mm Max® magazines.
Includes
- 16″ SOLGW Precision SPR barrel, converted to the LMT® MRP™ interface
- Low-profile gas block, nitride finish, installed, aligned, torqued and pinned with a stainless steel coiled spring pin
- Gas tube sized to the gas system, black nitride finish, installed
- SOT Standard Barrel Thread Protector, fitted (CNC-machined steel, black nitride finish)
- Vacuum-sealed, with a Zerust® corrosion-inhibitor tube in the bore (remove before firing)
- Barrel inspection record (SOT-BIR-001)
Options
- Headspaced bolt group: SOT Enhanced Microbest C158 MPI DLC+
- Headspaced bolt group: SOT Enhanced HM Defense, Black Nitride
- Headspaced bolt group: SOT Enhanced Microbest Super-Stake with Young Manufacturing HMB™
- Muzzle devices from other manufacturers, installed and timed — for a specific muzzle device, please ask before ordering
Matching headspaced bolt
Choose a bolt above and we gauge headspace with it in this barrel and record the pairing on the barrel inspection record, so the two ship as a matched set.
Full specifications, photos and the inspection standard
Shipping: we do not ship barrel assemblies to CA, CT, DE, DC, HI, IL, MD, MA, NJ, NY, RI or WA, or to Denver, CO or Cook County/Chicago, IL. Questions? Ask your local FFL.
WARNING: This product can expose you to chemicals including lead, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.
